Stop-valve.



T. POLLOGK.

STOP VALVE.

APPLICATION FILED MAR. 12, 1910.

Patented Sept 13,1910.

UNITED STATES "PATENT OFFICE.

THOMAS POLLOCK, 0F FOLKESTONE, ENGLAND, ASSIGNOR TO THE DOVER ENGINEER- ING WORKS, LIMITED, OF DOVER, ENGLAND.

STOP-VALVE.

Specification of Letters Patent.

Patented Sept. 13, 1910.

Application filed March 12, 1910. Serial No. 548,962.

To all whom it may concern:

Be it known that I, THOMAS POLLOCK, a subject of the King of Great Britain and Ireland, residing at Folkestone, in the county of Kent, England, have invented new and useful Improvements in Stop-Valves, of which the following is a specification.

My invention relates to improvements in stop-valves applicable for use with high pressure fluids, and particularly to that class of stop-valve in which a piston-valve is adapted to work in a ring of packing mounted in the diaphragm through which the fluid passes on its way from the inlet to the outlet.

According to my improved method of construction, a tubular sleeve of the same diameter as the piston-valve but separate therefrom is mounted co-axial therewith in the diaphragm. Upon opening the passage way through the stop-valve, the piston-valve is withdrawn from the position in which it was surrounded by the packing, this position being assumed by the sleeve which is caused to follow the movement of the valve. Under such conditions, the packing is protected from the cutting action of the fluid under pressure, not only when the valve is fully open, but at any intermediate position.

A valve embodying my invention is illustligated in the accompanying drawing, where O Figure 1 is a vertical section showing the valve in the open position and Fig. 2 a similar view showing the valve in a closed position.

Referring to the drawings, I provide a valve casing 1 having an inlet 2 and an outlet 3. This casing is furnished with a cap 4 adapted to receive a screwed spindle 5 whereby a cylindrical piston-valve 6 may be raised or lowered; said spindle being provided with a stufling-box and gland 7 of the usual character. The piston-valve 6 is connected with the head 8 of the valve-spindle in such a manner that by means of the handwheel 9 the spindle can be turned without necessarily rotating the valve. By means of the spindle 5, the piston-valve 6 is capable of being moved into or out of a packingring 10 mounted in the inner surface of a passage through the diaphragm 11, the diameter of this passage corresponding with that of the piston-valve 6. The packing 10 is held in position in the diaphragm 11 by means of a gland 12 adapted to be tightened upon said packing. Mounted in the passage through the diaphragm and co-axial with the valve is a sliding sleeve 14 the diameter of which corresponds with that of the valves. The sleeve may be supported on a spiral spring 15 adapted to insure its rising (when the valve is raised) until the position represented in Fig. 1 is reached; the valve being fully open and the packing 10 completely shielded by the sleeve 14. The fluid under pressure is now free to pass from the inlet 2 through the sleeve 14 to the outlet 3. WVhen it is desired to interrupt the flow, the piston-valve 6 is lowered until it arrives against the upper edge of the sleeve 14. On the movement being continued, the sleeve is forced down against the resistance of the spring 15 (in addition to that of the fluid under pressure) the piston-valve 6 following the sleeve 14; until the former occupies a position within the packing 10 previously occupied by the sleeve 11.

As the cutting off of the fluid under pressure is primarily effected by the face of the valve, as distinguished from its circumferential surface, the latter, on which the tightness of the valve ultimately depends, is not subjected to wear by reason of the cutting action of the fluid dealt with.

What I claim as my invention, and desire to secure by Letters Patent, is

1. In a stop-valve, the combination,with a packed diaphragm and a piston-valve adapted to work therein, of a cylindrical sleeve, mounted co-axially with the valve, but separate therefrom, and means for causing said sleeve to occupy a position within the I acking upon such position being vacated by the valve, substantially as herein described.

2. In a stop-valve, the combination, with a packed diaphragm and a piston-valve working therein, of a sleeve, separate from the valve, and following its movement and serving when the valve is open to shield the packing from the cutting action of the fluid under pressure, substantially as herein described.

8. In a stop-valve, the combination, with a valve-casing formed or provided with a packed diaphragm, of a piston-valve adapted to move into and out of thepacking, a I name to this specification in the presence sleeve co-axlal with and of the same d1ame of two subsorlblng Witnesses.

ter as the piston-valve and means for causing the said sleeve to f ollow the movements THOMAS POLLOCK' 5 of the said valve When being opened, sub- Witnesses:

stantially as and for the purposes set forth. FREDERICK PREBBLE,

In testimony whereof I have signed my GEORGE CoLLYER. 

